Background: Driving under the influence of alcohol, illicit drugs and certain medicines is not allowed worldwide. Roadside drug testing is considered an important tool for determining such behavior. In Spain, mandatory roadside oral fluid drug testing is carried out regularly. The aim of this study was to determine the prevalence of benzodiazepines and benzodiazepines in combination with other drugs in drivers, examine benzodiazepine concentrations in drivers, and analyze the association of these factors with age and sex.
Methods: This study assessed data on Spanish drivers with confirmed drug-positive results recorded by the Spanish National Traffic Agency (Dirección General de Tráfico) between 2011 and 2016, accounting for 179,645 tests and 65,244 confirmed drug-positive tests.
Results: Benzodiazepines were confirmed in 4.3% of all positive roadside drug tests. In most of those cases (97.1%), other substances were also detected, particularly cocaine (75.3%) and cannabis (64.0%). The frequency of benzodiazepine-positive drivers (OR, 1.094; 95% CI, 1.088-1.100) increased with age, while the frequency of drivers who tested positive for benzodiazepines in conjunction with other substances, compared with drivers who tested positive for benzodiazepines alone, decreased with age (OR, 0.903; 95% CI, 0.825-0.988). Nordiazepam (54.8%) and alprazolam (46.9%) were the most common benzodiazepines detected.
Conclusion: Concomitant use of benzodiazepines and other psychoactive substances was found to be a common behavior among drivers who tested positive on the road. It is important to raise awareness of all those involved in the consumption of driving-impairing substances (authorities, healthcare providers, patients and their families, etc.): roadside detection of driving-impairing substances is suggested, in addition to promoting the use of fewer driving-impairing medications and the provision of clear information to patients.
Keywords: Automobile driving; Benzodiazepines; Driving under the influence; Drug prescription; Oral fluid; Psychotropic drugs; Saliva; Street drug testing; Substance abuse detection.